During the last years touch screens has been more and more popular in many devices such as mobile phones, tablets and computers. On a touch screen no regular keyboard is used, instead the user touches the screen to give input to the device. One problem with a touch screen is that the hand is held in front of the touch screen and occludes the touch screen. This makes it more difficult to read the text on the touch screen and also touch the touch screen in a more precise manner.
A related case is if a person writes on a white board. Sometimes it is difficult for a reader to read the text on the white board because the hand, arm and even the body of the writing person obscures what's written on the white board. The limbs of the person may also distract the readers.
A technology that also has been more popular during the last years is augmented reality. Augmented reality means that some information is displayed on a display improving the experience for the user. For example, a picture is recorded by a camera. When the picture is displayed on a display some information is added on the display. This information may e.g. be information regarding what can be seen on the display. If a picture is recorded of a house and the camera is connected to a GPS-recorder and a compass, the information that's added on the display may e.g. be who owns the house. This technique is well known in the prior art.